Investigating intermolecular interactions at the membrane-catalyst interface to improve the performance and durability of anion exchange membrane water electrolysis

Abstract

Improving the hydrogen production efficiency and durability of anion exchange membrane-based water electrolysis (AEMWE) necessitates not only developing high-performance anion exchange membranes (AEMs) and catalysts but also reducing the interfacial resistance of the membrane electrode assembly (MEA). A methoxyethyl group, which can interact with the ion-conducting groups within the AEM structure, was incorporated into the AEM polymer matrix to enhance the interfacial adhesion between the membrane and catalyst layers of the MEA. The developed AEMs exhibited improved intermolecular interactions, confirmed by spectroscopic analyses and simulations. Furthermore, the incorporation of the methoxyethyl group into the AEM induced AEM–ionomer interactions after MEA fabrication, particularly for poly(aryl piperidinium)- and poly(aryl ether)-type polymers, strengthening membrane–catalyst interfacial adhesion. These results were further confirmed by the adhesion, as estimated from the surface energies of the polymeric components via catalyst delamination tests. Introducing the methoxyethyl group improved the AEMWE cell performance by 25 % at 7.09 A cm−2 and 2.0 V, while also enhancing cell durability. According to the findings of this study, membrane–catalyst adhesion strength in the MEA can be effectively controlled by incorporating functional groups capable of interacting with the ionomers within the membrane.